Design of a Wideband Equal Power Divider and Multiple Phase Shifter for Variable Polarization

A hybrid microwave passive network having equal power division and variable phase shifting ability within a wideband is proposed. The hybrid network consists of a wideband noncoupled-line microstrip balun network and two 90 degrees phase shifters derived from the same balun. The microstrip network has an advantage of equal power division and 10 dB return loss within a wide bandwidth from 2.6 GHz to 4.1 GHz. The four output ports of the network provide 0 degrees, 90 degrees, 180 degrees, and 270 degrees phase shift with respect to the input signal throughout the operating band. The amplitude and phase imbalance between the four output ports are within 0.9 dB and +/- 8 degrees, respectively, along with the port isolations are below -15 dB. The overall dimensions of the device are made compact (3.2 lambda x 2 lambda x 0.032 lambda) at the center frequency of 3.3 GHz and designed on low cost FR-4 (epsilon(r) = 4.4) substrate.